Residential refrigerator battery drain

[Mogulite]

Purchased our 34pa in March. We do about 6-8 weeks a year of dry camping a year. We noticed right off that the batteries were in constant need of being charged.

So we added four more solar panels to the one that came with it. Had my RV tech install the GoPower 760 watt system. It’s great during the day charging the batteries but overnight the batteries were still down to 11.5-11.6. So I installed four Lifeline AGM’s at $1,600 and in the morning, same result, 11.5-11.6. Please don’t tell me how happy you are with your lithium batteries as that ship has already sailed after spending $1,600 on AGM’s.

Overnight, the only things using electricity besides the Whirlpool refrigerator are the bedroom fan, a weather system, an electric toothbrush and two Ember coffee cups. Ember coffee cups are cups you charge that keep your coffee warm.

Do I need to unplug the misc. unnecessary stuff before going to bed? They don’t seem like they would drain that much. Or is just the nature of the beast? The beast being the residential refrigerator.

[zombiewoof]

Being an insomniac has given me the opportunity to monitor boon docking energy usage through the night. I have a Victron SmartShunt so I can see accurate energy usage coming from my batteries. I have a 2021 Bus so it is not apples to apples, but your energy usage should be the same or less. During the night, with nothing running, there is a constant 180 watt load on the house batteries. When the refrigerator kicks on it goes to 260-280 watts. From the time I turn off the generator at 8PM and the time I start it back up 12 hours later I consistently use 160-180 amp hours of energy. With four AGM batteries you have a total of 440 amp hours at 12V or thereabouts? Doing the math you should still have 60% capacity left. This equates to about 12.15 volts open circuit. Since there is a load on the batteries this voltage will be in the high elevens. So, given your numbers it does not seem unreasonable though I question the quiescent load on your batteries. All of this assumes your batteries are fully charged and at float before you unplug for the night. I would expect with a 34PA versus my Bus your quiescent loads would be less and your voltage in the morning slightly higher. If you could put a Victron shunt on your house batteries it would give you a much clearer picture of what is going on.

[Mogulite]

Thanks for the response. I was hoping someone with electrical knowledge would break it down for me. Definitely feel a bit better about the situation now.

Would love to hear from someone with a similar coach to see if they’ve experienced the same thing. Just worried that I may have an electrical issue I’m unaware of using battery power at night. Also don’t want to damage my new batteries by running then down too low.

[wolfe10]

You have mentioned the DISCHARGE, but not the CHARGE part of battery use.


Tell us about how you recharge the batteries after they are discharged to 11.6 VDC


Also, which 4 Lifeline AGM's do you have (voltage and amp rating)?

[SteveJ.]

Boondocking/dry camping without a shunt battery monitor is like driving your coach without a fuel gauge. Yes, it can be done, but it is a hassle and can be stressful.

[DavidEM]

You obviously have an inverter to power the fridge and other AC loads. Does it have a charger? What is the capacity of each?

With your high amp hour usage, solar by itself will not keep the batteries up. You need to put in an extra 100 amp hours or so each day. If your inverter has a charger built in, use that to add more amp hours back to your system by running your generator for a couple of hours each day.

And as SteveJ advises above, add a shunt based battery monitor to see what really is going on rather than guessing with inaccurate voltage readings and relying on others fo usage info. Victron makes one of the best, Renogy second best, but a cheap QWorks battery monitor I bought for less than $50 on Amazon works great for me.

And don't let your AGM batteries run down below a real 50% SOC too often for best life.

David

[jacwjames]

I have a residential refrigerator. 4 flooded batteries. I boon dock and have no problem lasting the night. I will usually run the generator right before bed, bringing the charge up to ~90%. 8 hours later when I get up I still have 75% battery left.

No other loads then the refrigerator.

I do have 325 watt solar panel and during the sunny days it will keep the batteries up.



So you must have one heck of a parasitic load. I'd suggest getting a amp meter and checking the circuits to figure out what's going on.

[Mogulite]

Originally Posted by wolfe10

You have mentioned the DISCHARGE, but not the CHARGE part of battery use.


Tell us about how you recharge the batteries after they are discharged to 11.6 VDC


Also, which 4 Lifeline AGM's do you have (voltage and amp rating)?

My AGM batteries are GPL-4CT and to recharge I run the generator to get them up to 12+, then let the solar do the rest.
My solar controller has a charge percentage monitor that I can check.

[DavidEM]

Originally Posted by Mogulite

My AGM batteries are GPL-4CT and to recharge I run the generator to get them up to 12+, then let the solar do the rest.
My solar controller has a charge percentage monitor that I can check.

Your solar controller SOC indication will just be an approximation as it is based on battery voltage. Battery voltage is based on SOC plus the current being drawn from the battery. It can be off 25%.

Use a shunt based battery monitor to really know your SOC.

David

[bpu699]

Originally Posted by Mogulite

Purchased our 34pa in March. We do about 6-8 weeks a year of dry camping a year. We noticed right off that the batteries were in constant need of being charged.

So we added four more solar panels to the one that came with it. Had my RV tech install the GoPower 760 watt system. It’s great during the day charging the batteries but overnight the batteries were still down to 11.5-11.6. So I installed four Lifeline AGM’s at $1,600 and in the morning, same result, 11.5-11.6. Please don’t tell me how happy you are with your lithium batteries as that ship has already sailed after spending $1,600 on AGM’s.

Overnight, the only things using electricity besides the Whirlpool refrigerator are the bedroom fan, a weather system, an electric toothbrush and two Ember coffee cups. Ember coffee cups are cups you charge that keep your coffee warm.

Do I need to unplug the misc. unnecessary stuff before going to bed? They don’t seem like they would drain that much. Or is just the nature of the beast? The beast being the residential refrigerator.

Your ceiling fan will use a lot of juice. They pull around 3 amps at low speed…

That’s 30-40 amp hours over night. (Assuming an 12 hour night which is generous… solar output usually starts dying down around 5 pm, comes back to full output around 9-10 am)

Fridge pulls 150 watts or so, that’s 10 amps or more per hour… that’s 120-150 amp hours…

Inverter pull 2-3 amps per hour… that’s 36 amp hours…

It adds up.

And, I bet you have a basement freezer, and more.

Hook up an amp meter to your house battery, Amazon has the for $50…


In my rv I had a basement freezer, and a small college fridge, 3 100 Amp agm’s. By morning it ran them down to 12.2-12.3 volts. I don’t go under 12v…

In my scenario I have 300 amp hours, but only use 150 amp hours….

You sure your batteries are fully charged when you goto sleep? A 750w solar system might put out 600w on a good day.

[Mark_K5LXP]

Echo the above, without an Ah meter on your batteries you have no idea where your batteries are. It doesn't take much of an imbalance of charge vs discharge to be in deficit mode and after a few days you're in the red. I think you're both undercharging your batteries and you may have more loads than you have accounted for. Get the monitor and answer those questions.

Depending on the draw at 11.6V you're around 50%. You still have a lot more to go. The nervous nellies telling you to stop using your batteries at 50% are spreading misinformation. You will likely never come close to wearing out your batteries through cycling, so even down to 80% DOD is well within your "safe" operating range. As a weekend warrior camper I have no qualms taking them down 100%. So set your discharge threshold more realistically, get a battery monitor and take all of the mystery out of it.


Mark B.
Albuquerque, NM

[Persistent]

I agree with Mark. You will not "damage" your Lifeline AGM batteries by drawing them down to 11.5 volts. They likely get 300 to 400 recharge cycles drawing them down to 11.0 volts.

The actual static voltage is going to be higher than 11.5. You would have to stop charging and discharging for a while to see static voltage. You will probably get 600 to 800 recharge cycles with your present profile.

It takes 14 to 18 hours charging with a high quality charger like the one built in to your RV to fully charge a lead acid battery. You can put a substantial charge into it in 4 hours if charging at maximum capacity. A 500 amp hour battery bank may absorb 90 amps when it is deeply discharged. Charging rate tapers as the battery charges.

Run the generator in the morning. It will provide high charging rate when the solar is not providing much. Let the solar finish the charge. Later in the day, solar will be dropping off at the same time as the battery charge is tapering off.

Periodically you need to bring the lead acid batteries to full charge to prevent sufation. This will take 14 to 18 hours. Possibly this should be done once per week. Start the generator at 6 am. Run it until 10 am. Let the solar finish for an additional 10 hours. Try not to use any more 120 volt or 12 volt power than absolutely necessary during this period so the batteries get a full as possible.

If you had a good current measuring battery monitor you could monitor the charge and see how much extra power is available. Generally the generator provides plenty. The solar not so much.

[dssl]

You can figure out the state.of charge by the voltage, but do so after the charger shuts off for the night.

I am in agreement that a battery monitor is something that will help you understand what is going on and you should strongly consider.

I have a 2015 32SA and the residential refrigerator draws about 10 amps from the batteries when the compressor is running.

One thing that surprised me was my entertainment circuit draws 5 amps from the batteries when everything is off, as a result keep the entertainment circuit breaker off when I can when boondocking.

If your 4 batteries are fully Charged and nothing is wrong it should be able to make it through the night.

It's important with lead acid batteries that you fully charge them every day, otherwise they won't last.

[Mogulite]

Thank you so much for the very helpful information. We’re still dry camping so I’ll charge the batteries for four hours this morning. I will definitely get a battery monitor.

Thanks again